ebb and flow system questions

[dmackk]

I just acquired a system that has a 4x8ft. tray and 4x4ft. 12" deep reservoir (100 gallons?) The system was used and I just spent the day cleaning the whole thing out. I have 2 1000w lamps 1 mh and 1 hps that rotate on a sun circle and are under parabolic hoods . I plan on obtaining some cuttings that are around 3" tall. Here are my questions:

What should the ppm be? (I''ll be using GH line of flora series unless flora nova is better)
How close should I put the lights?
How often should I run the pump? (4"rockwool cubes)
It doesn''t seem like the tray drains completely. There is always some water left in the grooves. Is that a problem?
How often do I have to change the water/nutrients in the reservoir and what may be a good method to do that? I just did it today with a shop vac and that sucked.

Thanks in advance for the help. I''ve done this once before and got some really bad advice from the person that I purchased the system from.

[resinous]

As far as your ppm's go, follow the directions from GH as far as how to mix for the size plants your girls are in. You can start them in 600 ppm. You ramp it up eqch week until you are near 1200-1800. Then the last couple weeks you ramp down a bit back to 1000ppm. The last 7 days is just flush with ph'd water. Read the charts that come with your nutes.

How close to put the lights? As close as you can so that the tops of your plants are the perfect 76 degrees. This time of year heat may be a factor in how close you can run the bulbs but closer is better. Too much heat and the buds remain light and airey. Indoors you want smaller and shorter plants, you 1000 watts can only penetrate 2 feet into the canopy so 3 foot plants are a good indoor size.

Keep in mind that when you flower your plants they may stretch 2 to 3 times their former height within a couple weeks of the flip. Keep this is mind as to how tall to veg them. Not all strains stretch the same, purple kush barely strertches at all.

How ofter to flood? In Rockwool you can just flood once a day, and never at night. Rockwool holdss a lot of water compared to clay pebbles, which do need flooding every 3 hours. I think once a day is plenty in rockwool.

You want the table to dry completely because at night the powdery mildew can hit if the humidity is high in the area, and that water in the grooves can affect humidity. I would relevel the flood table so it drains a little better.

Nitrogen is used up from your nutrient solution in 6 days so most people reccomend changing the solution every week. Keep in min some people never change their res except to re-top it so do what you feel comfortablew with.

And more questions just ask.

[local]

if you have a 4 x 4 , 12 inch tall res. its probably not 100 gallons

i have a 3 x 4 , 12 inch tall res. and its a 40 gallon.......wouldnt want you to over fertilize

[dmackk]

Thanks for the help.

So, when I initially add my nutes in the proper proportions, after six days the nitrogen will be eaten by the plants. If I simply add more nutes (and water due to evaporation), how will the ppm be affected. In other words, when the plants eat the nitrogen and other nutes, does the ppm of the solution go down?

Ideally I suppose you would want to empty the reservoir every week, but being in an apartment, where I have to either bucket it out or shop vac it, I'd rather not have to do it that often.


Thanks!!!

[salmonmank]

Just a quicky- 7 gallons per cubic foot for water.

[dmackk]

Thanks, Salmonmank. 4x4x12"=16 cubic feet=112 gallons

[local]

thanks Thanks for the help.

So, when I initially add my nutes in the proper proportions, after six days the nitrogen will be eaten by the plants. If I simply add more nutes (and water due to evaporation), how will the ppm be affected. In other words, when the plants eat the nitrogen and other nutes, does the ppm of the solution go down?

Ideally I suppose you would want to empty the reservoir every week, but being in an apartment, where I have to either bucket it out or shop vac it, I'd rather not have to do it that often."

sorry about the bad res. info....I have a 40 gallon botanicare res. that is 3 feet long and only 2 feet wide and 12 inches tall.

I empty, clean out and then refill my res. every week, my nutes say never to add more nutes to any soloution...always add to fresh water..I assume it is to avoid nutrient lock up as well as excessive salt buildup....if you dont want to do it every week just keep topping your res. off with ph balanced water until your can empty it out completely and wash it.

also try connecting a garden hose to your pump and pumping the water out that way ...works for me

peace